1. Field of the Invention
This invention relates to a manufacturing method and apparatus for forming an elongate body having thickness change such as a window molding and the like, and particularly applicable to a manufacturing method and apparatus for forming a window molding for automobiles that has vertical members molded into a section different from that of a horizontal member.
2. Description of Related Art
A convention window molding for automobiles is shown in FIG. 22 to FIG. 25.
In the figures, the window molding is composed of a pair of vertical members V and a horizontal member H molded of a synthetic resin material. The vertical members V are respectively fitted into gaps between right and left edges of a front window glass 1 and a window frame 2. The vertical members V have their heads 151 protruded higher than a head 161 of the horizontal member H from the front surface of the window glass 1. Thus, rainwater swept by a wiper is prevented from overflowing into a side window 3. Further, each head 151 of the vertical member V has a guide groove 152 at its glass side so as to drain the rainwater downward along the right and left edges of the window glass 1. On the other hand, the head 161 of the horizontal member H has substantially a plate-like shape in consideration of aerodynamic characteristics. Namely, it is smoothly continuous from the front surface of the window glass 1 to an upper surface 2a of the window frame 2 which forms a front margin of a roof 4 of the car body. The heads 151 and 161 of the members H and V respectively have seal lips 153 and 162 at their frame side. The seal lips 153 and 162 are elastically contacted with the upper surface 2a of the frame 2 so as to close the gap between the window glass 1 and the frame 2.
There is proposed a window molding for automobiles that can guide and drain rainwater flowing from a front window or a rear window toward a window frame, as well as rainwater flowing from the frame toward the window, downward along the edges of the window glass, in order to ensure a relatively clear view from the car when it rains. For example, Japanese Laid Open Patent Publication No. 1-153325 discloses this type of window molding. The window molding of the above publication has its vertical members and horizontal member provided with heads substantially of a plate shape which are continuous to the front surface of the window glass. Guide grooves are formed between the heads and a window frame. On the other hand, Japanese Laid Open Utility Model Publication No. 61-138710 shows another window molding for automobiles in which a lip is disposed slantingly from a gap between a rear window glass and a window frame, toward the window frame. In this molding, there are provided two guide grooves, one facing the rear window glass and the other facing the window frame.
These moldings are typically molded by extrusion into an elongate shape in consideration of production costs or the like. Accordingly, it is necessary to manufacture vertical members and a horizontal member separately, and thereafter join the vertical members and the horizontal member via another separately molded joint, in case the vertical members and the horizontal member are formed into different sections. This results in increasing the number of parts and increases production and assembly time, thereby augmenting the manufacturing costs.
Thus, there is a request for a manufacturing method for molding an automobile window molding into a specific section and changing sections of vertical members and a horizontal member thereof.
Generally, there is a technique corresponding to this method that extrudes the window molding into a section of a vertical member and that presses it by a press roller to form a horizontal member thereafter.
However, in case of setting a pressed area on the window molding and changing a shape of the pressed area to make the vertical member and the horizontal member into different sections from an original section of the window molding, desired sections cannot be obtained if there is nonuniformity in the original section thereof at the time of extrusion. In such condition, the horizontal member is partially bulged and may exhibit a poor appearance even if it is intended to form the horizontal member flat and lessen the height thereof.
Moreover, in case of making the horizontal member by controlling pressure of the press roller onto the window molding which is extruded into the section of the vertical member, the window molding is to be cut into a length fitted into the gap between the windshield and the window frame of the car. Thus, it is necessary to cut the molding at each center of the vertical member. However, on that condition, the length of the vertical member will differ in case there is an error in distance to the center of the vertical member. This results in a poor appearance when the molding is assembled to the car.
Thus, when manufacturing the window molding having the vertical member and the horizontal member of different thicknesses, it is required to cut the window molding so as to include the horizontal member as well as a pair of vertical members of the same length. However, it is difficult to automatically measure a length of a thickness changing portion of the window molding which has the vertical members and the horizontal member of different sections and which forms a guiding portion for drainage along a perimeter of the windshield.
A manufacturing method of the window molding will be described below. First, in an extruding step, a synthetic resin is extruded by an extruder (not shown) into the same section as a section of a vertical member V which has an inner support 201 at a lower end, as shown in FIG. 24. Next, in a cooling step, an extruded body is cooled and hardened. In a subsequent cutting step, the body is cut into a constant length including a pair of vertical members V and a horizontal member H, thereby obtaining the primary molded product of FIG. 24. This primary molded product has the same section on its whole length as the vertical member V. The primary molded product has a guide groove 204 between a head 203 and an outer support 202. In an adhesive coating step thereafter, an adhesive is coated on a surface of the guide groove 204 at a portion to be the horizontal member H of the primary molded product. Subsequently, in a pressing step which is carried out in another production line different from the above production line, the head 203 of such portion is pressed downward and collapsed so as to be placed and overlapped closely on the outer support 202. Thereby, as shown in FIG. 25, an automobile window molding is completed as a final molded product which has a horizontal head 203H successively formed between a pair of vertical heads 203V.
However, in this method, the final molded product is completed by another production line including an adhesive coating step and a pressing step, after the primary molded product is obtained in one production line including the extruding step, the cooling step and the cutting step, as described above. Thus, two different production lines are necessary to obtain the final molded product. Therefore, there is room for improvement in view of productive efficiency. Moreover, there is a possibility that the adhesive coated on the guide groove 204 in the adhesive coating step would leak out of the gap between the horizontal head 203H and the outer support 202, which are put on each other in the pressing step, so that an appearance of the final molded product is adversely affected.